The number of records loaded in a sync and the number of additions to the destination table may not always match due to the type of data synchronization you are using in Airbyte. If you are using incremental data synchronization, when you modify a record in the source system and then perform a sync, an updated version of the record will be copied from the source and appended to the raw table and the final table in the destination. However, even though the source only contains two records, both the raw and normalized destination tables contain three records each. This is because both the current and the previous version of the record with an
id of 2 will be stored in each destination table. This could be why you are seeing fewer additions to the destination table than records loaded in a sync. [source](
https://airbyte.com/tutorials/incremental-data-synchronization#step-6) If you are using full refresh data synchronization, the entire source table is appended into the destination. Additionally, only the data from the current and the previous sync have been normalized. This could also be why you are seeing fewer additions to the destination table than records loaded in a sync. [source](
https://airbyte.com/tutorials/full-data-synchronization#step-8) If you are using Change Data Capture (CDC) synchronization, all of the intermediate states for each record have been captured and are stored in the destination. This is different from non-CDC incremental replication, in which only the state of the records in the source table at the moment the sync was executed was captured, and all intermediate states were lost. [source](
https://airbyte.com/tutorials/incremental-change-data-capture-cdc-replication) Lastly, if you are using Refresh and Remove Records Syncs, only data that was newly synced since the refresh was initiated will be displayed in the destination’s final tables. [source](
https://docs.airbyte.com/operator-guides/refreshes#refresh-and-remove-records) Therefore, the type of data synchronization you are using could be why you are not seeing as many additions to the destination table as you see records loaded in a sync.